Blimps were once filled with hydrogen, but now helium is used instead. Why is helium a better choice than hydrogen?
a Hydrogen is no longer available in pure form.
b Helium is cheaper than hydrogen.
C Hydrogen is flammable, while helium is not.
d Helium is lighter than hydrogen.

Me . based on the data in your tables, did the light-colored moths have a higher or lower survival rate after the industrial revolution?

Suppose you have monohybrid pea plants in your garden and find that they produce round seed to wrinkled seeds in the ratio of 3: 1. if the allele are designated (r & r) receptively. what is the probable genotypes of the round seeds which produced f 1 ? rr & rr rr only rr & rr rr only rr only

Which of these parts of the membrane large moecules pass through it ?